Abstract:
Steel concrete composite beams are commonly used in construction, where they are connected to metal deck filled concrete slabs using shear connectors. These connectors play a crucial role in resisting horizontal shear forces between the steel beam and concrete slab, enabling them to act as a single unit. Among the various types of shear connectors used, Rebar connectors are preferred due to their ease of installation and cost-effectiveness. However, limited research exists in the published literature regarding the flexural behaviour of composite beams with rebar connectors. To address this gap, an experimental investigation was conducted in this study to investigate the flexural behaviour of steel concrete composite beams with rebar connectors through single-point load tests. The test specimens were designed to examine the influence of concrete strength and spacing of rebar connectors. Additionally, a control beam with 13% composite action (CB) was included for comparison, and an additional steel beam was tested separately to measure its strength in a single-point load test.
The behaviour of the composite beams was compared to that of both the control beam and the steel beam as well. Furthermore, the moment capacities obtained from experiment were compared with the theoretically predicted capacities. Various aspects were analyzed, including the moment versus midspan deflection curve, ultimate moment capacity, corresponding deflection, and interfacial slip between the steel and concrete. The failure behaviour of the test specimens was also examined. Typically, the failure of composite beams was initiated by flexural shear cracks in the concrete slab, followed by local buckling of the steel flange. Separation at the interface between the metal deck sheet and the steel flange, as well as the concrete slab, was observed at failure.
The response (moment, deflection, shear etc.) of the composite beams was significantly influenced by the composite action. The maximum enhancement in the ultimate moment capacity of the composite beam specimens was found to be 43% compared to the steel beam. The presence of shear connectors at the steel concrete interface resulted in 84% reduction in maximum vertical deflection compare to steel beam only and 70% reduction in maximum horizontal slip at the interface between concrete slab and steel flange compare to control beam.
Moreover, the moment capacities obtained from experiment were found to exceed the predicted capacities for most of the specimens, except for the specimen with highest composite action. These findings may contribute to a better understanding of the behaviour and performance of steel concrete composite beams with rebar connectors.